Bioactive Peptides Originating from Gastrointestinal Endogenous Proteins in the Growing Pig: In Vivo Identification

Area of Science:

• Biochemistry
• Molecular Biology
• Animal Nutrition

Background:

• Gastrointestinal endogenous proteins (GEP) are recognized as potential sources of bioactive peptides.
• Previous in silico and in vitro studies suggested GEP-derived peptides possess biological activity.
• The in vivo presence of these peptides in the digestive tract lumen remained unconfirmed.

Purpose of the Study:

• To investigate the generation and bioactivity of GEP-derived peptides in vivo.
• To assess the angiotensin-I-converting enzyme (ACE-I) inhibition and antioxidant properties of peptides from growing pigs fed a protein-free diet.

Main Methods:

• Analysis of stomach chyme (SC) and jejunal digesta (JD) fractions from pigs.
• Assays included ACE-I inhibition, DPPH radical scavenging, ferric reducing antioxidant power (FRAP), and lipid peroxidation inhibition (MLP).
• Identification of novel peptide sequences linked to observed bioactivities.

Main Results:

• Jejunal digesta fractions demonstrated significant ACE-I (81%) and DPPH (94%) inhibition.
• Stomach chyme fractions showed microsomal lipid peroxidation (MLP) inhibition ranging from 15-39%.
• Over 180 novel bioactive peptide sequences were identified, including a porcine serum albumin-derived peptide.

Conclusions:

• This study provides the first in vivo evidence for GEP as a source of bioactive peptides.
• Findings highlight the potential role of GEP-derived peptides in mammalian nutrition and health.
• The identified peptides may have future pharmaceutical applications.